This month, we're updating it, and we want to make sure it's as complete as possible. For that, we need your help. Check out the Google spreadsheet and see if it includes the protected lanes you know of. If it doesn't, or if the information is wrong, send a note to maryam@peopleforbikes.org with your corrections, additions or tips.

Just this week, Bloomberg used the inventory as the lead statistic in a story explaining the role of protected lanes in attracting young workers. As the Federal Highway Administration prepares its landmark study of protected lanes' safety, its researchers have drawn on the inventory, too.

What is a protected bike lane?

As part of the Green Lane Project's newly revised style guide, we've spelled out a protected bike lane's three characteristics:

Physical separation. Protected bike lanes have some sort of physical, stationary, vertical element between moving motor vehicle traffic and the bike lane. Examples of vertical separation include plastic posts, landscaping, bollards, curbs, planters, raised bumps or parked cars. Protected bike lanes can be at street level or raised, either to sidewalk level or a level in between street and sidewalk level. Protected bike lanes can be either one-way or two-way. Paint alone does not create a protected bike lane.

Exclusively for people on bikes. Protected bike lanes must define and allocate space exclusively for people on bikes, not shared with pedestrians or motorized traffic except for brief mixing zones where necessary and at intersections. If the lane is at sidewalk level, there must be continuously defined separate space for people on bikes and people on foot in order for the facility to be considered a protected bike lane.

On or adjacent to the roadway. Protected bike lanes are part of the street grid. In some instances, a protected lane may be separated from the road by landscaping or other features, but it runs parallel and proximate to the roadway. This distinguishes protected bike lanes from off-street pathways, such as those that follow waterways or rail corridors.

Protected bike lanes are not:

Multi-use or shared paths; space must be designated exclusively for people riding bicycles.

Buffered bike lanes; there must be some type of vertical object delineating the space.

Conventional bike lanes that are painted green.

As this concept continues to spread around the continent, it'll become harder to keep up with everything going on. That's a problem we can all be proud to have.

The Green Lane Project is a PeopleForBikes program that helps U.S. cities build better bike lanes to create low-stress streets. You can follow us on Twitter or Facebook or sign up for our weekly news digest about protected bike lanes. Story tip? Write michael@peopleforbikes.org.